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interfaces-bond(5) File Formats Manual interfaces-bond(5)


interfaces-bond - Bonding/LAG extensions for the interfaces(5) file format


The Linux implementation for Ling Aggregation Groups (LAGs) is called bonding, whereas a LAG interface is called bond. The Linux bonding implementation supports active/passive setups, classical EtherChannels as well as LACP (802.3ad).

The following options set up bonding/LAG interfaces with ifupdown-ng.

See and for more information.


A bond interface must have at least one member port set. All other options are optional.

bond-members list of interfaces

Denotes the physical member interfaces to form this LAG. For compatiblity to ifupdown1 and ifupdown2 slaves as well as bond-slaves are an alias for this option. This option is required.

bond-mode mode

Denotes the mode for this LAG. The mode can be given as string or as numerical value. Valid values are balance-rr (0), active-backup (1), balance-xor (2), broadcast (3), 802.3ad (4), balance-tlb (5), balance-alb (6). The default is balance-rr.

bond-xmit-hash-policy policy

Denotes the hash policy/algorithm used to distribute packets across the physical links. This only applies for modes balance-alb, balance-tlb, balance-xor, and 802.3ad. The policy can be given as string or as numerical value. Valid values are layer2 (0), layer3+4 (1), layer2+3 (2), encap2+3 (3), and encap3+4 (4). The default is layer2.

bond-min-links number

Denotes the minimum number of available links before turning on carrier.

bond-miimon interval

Denotes the MII link monitoring frequency in milliseconds. This determines how often the link state of each slave is inspected for link failures. A value of zero disables MII link monitoring. The default is 0.

bond-use-carrier bool

Denotes wether miimon uses MII or ethtool ioctls vs. the netif_carrier_ok() call to determine member link status. A value of 1 enables the use of netif_carrier_ok(), a value of 0 will use the deprecated MII / ETHTOOL ioctls. The default is 1.

bond-updelay delay

Denotes the delay in milliseconds before considering link up, in milliseconds. The default is 0.

bond-downdelay delay

Denotes the delay in milliseconds before considering link down, in milliseconds. The default is 0.

bond-all-slaves-active bool

Denotes wether duplicate frames (received on inactive ports) should be dropped (0) or delivered (1). The default is 0.

bond-packets-per-slave num_packets

Denotes the number of packets to transmit through a member before moving to the next one. When set to 0 then a slave is chosen at random. The valid range is 0 - 65535; the default value is 1. This option has effect only in balance-rr mode.

bond-lp-interval interval

Denotes the interval in seconds between sending learning packets to each members peer switch. The valid range is 1 - 0x7fffffff; the default value is 1. This option has effect only in modes balance-tlb and balance-alb.

bond-resend-igmp number

Denotes the number of IGMP membership reports to send after a link failover happend. The valid range is 0 - 255; a value of 0 prevents the IGMP membership report from being issued in response to the failover event. The default is 1. This option is useful for bonding modes balance-rr, active-backup balance-tlb and balance-alb, in which a failover can switch the IGMP traffic from one slave to another.


The following options are only valid in LACP (802.3ad) mode.

bond-lacp-rate rate

Denotes the rate of LACPDU requested from the peer. The rate can be given as string or as numerical value. Valid values are slow (0) and fast (1). The default is slow.

bond-ad-select mode

Denotes the 802.3ad aggregation selection logic. The mode can be given as string or as numerical value. Valid values are stable (0), bandwidth (1) and cound (2). The default is stable.

bond-ad-actor-sys-prio priority

Denotes the LACP system priority. The allowed range is 1 - 65535. The default value is 65535.

bond-ad-user-port-key key

Denotes the upper 10 bits of the port-key. he values can be from 0 - 1023. The default is 0.


The following options are only valid in active/passive setups.

bond-primary interface

Denotes the primary member interface The specified device will always be the active slave while it is available. The primary option is only valid for active-backup, balance-tlb and balance-alb mode.

bond-primary-reselect policy

Denotes the reselection policy for the primary member interface. Valid values are always (0), better (1), and failure (2). The default is always.

bond-fail-over-mac mode

Denotes whether active-backup mode should set all member interfaces to the same MAC address at enslavement (the traditional behavior), or, when enabled, perform special handling of the bond's MAC address in accordance with the selected policy. Valid values are none (0), active (1), follow (2). The default is none.

bond-num-grat-arp count

Denotes the number of peer notifications (gratuitous ARPs and unsolicited IPv6 Neighbor Advertisements) to be issued after a failover event. The valid range is 0 - 255; the default is 1.

bond-num-unsol-na count

This is an alias for bond-num-grat-arp

bond-peer-notif-delay interval

Denotes the interval in milliseconds, between each peer notification (gratuitous ARP and unsolicited IPv6 Neighbor Advertisement) issued after a failover event. The default is 0 which means to match the value of the link monitor interval.


The following options configure ARP link monitoring. The ARP monitor works by periodically checking the slave devices to determine whether they have sent or received traffic recently. Regular traffic is generated via ARP probes issued for the addresses specified by the bond-arp-ip-target option.

bond-arp-interval interval

Denotes the frequency in milliseconds to send ARP probes.

bond-arp-ip-target IPv4 address

Denotes the IP addresses to use as ARP monitoring peers when bond-arp-interval is > 0.

bond-arp-validate mode

Specifies whether or not ARP probes and replies should be validated in any mode that supports arp monitoring, or whether non-ARP traffic should be filtered (disregarded) for link monitoring purposes. Valid values are none (0), active (1), backup (2), all (3), filter (4), filter_active (5), and filter_backup (6). The default is none.

bond-arp-all-targets mode

Denotes the number of bond-arp-ip-targets that have to be reachable to consider the member interface to be up. Valid options are any (0) and all (1). The default is any.


A bond using two links and LACP (802.3ad):

auto bond0
iface bond0
	bond-members eth0 eth1
	bond-mode 802.3ad
	bond-xmit-hash-policy layer3+4
	bond-min-links 1
	address 2001:db8::42/64


Maximilian Wilhelm <>